Take-up lever for a sewing machine and protecting cover

ABSTRACT

A thread take-up lever of a sewing machine is mounted in the hollow machine frame and has a hook-shaped free end engaging the sewing thread and being movable between an upper and a lower dead center position. The machine frame is formed in its front wall with an opening substantially closed by a cover protecting the hook-shaped end of the thread take-up lever and being formed with slots permitting insertion of a thread into the hook-shaped end of the lever in any position of the latter.

States Paten 1191 Jan. 1, 1974 [5 TAKE-UP LEVER FOR A SEWHNG 977,630 12/1910 Hohmann 112/241 HIN AND PROTECTING COVER 2,063,280 12/1936 Waterman 112/241 [75] Inventor: Noboru Kasuga, Tokyo, Japan [73] Assignee: .llanome Sewing Machine Co. Ltd., jnmary 12m; i g i Knzmamch Tokyo Japan tl0rney- 1c ae tr1 er [22] Filed: June 1, 1972 [21] Appl. No.: 263,387 [57] ABSTRACT A thread take-up lever of a sewing machine is [30] Foreign Apphcauon Pnonty Data mounted in the hollow machine frame and has a hook- June 9, 197l Japan 46/40193 Shaped f end engaging the Sewing thread and being movable between an upper and a lower dead center [.22] US. Cl. 112/241 position The machine frame is formed in its from wall [J1] Dosh 49/00 with an opening substantially closed by a cover pro- [58] Fleld 01 Search 112/241, 242, 243, tecting h hook shaped end of the h d k 1 12/2441 96 lever and being formed with slots permitting insertion of a thread into the hook-shaped end of the lever in [56] References C'ted any position of the latter.

UNITED STATES PATENTS 3,561,002 2/l97l Robert 112/24] 7 Claims, 7 Drawing Figures PATENTEDJAN 1 19H 3.782.312

' sum 1 or '5 PATENTEJM x 1914 same or 5 PATENTED 1 74 SHEET k [If 5 PATEHTEDM 1 I974 SHEET 5 [IF 5 TAKE-UP LEVER FOR A SEWING MACHINE AND PROTECTING COVER BACKGROUND OF THE INVENTION The invention relates to the thread take-up lever of a sewing machine for pulling a sewing thread from a thread source, for instance a spool, mounted at an appropriate position on the machine frame.

In sewing machines known in the art, the thread takeup lever has a free end formed with an eye therethrough through which the thread is threaded, and this free end of the lever projects in machines known in the art outwardly of the machine frame to permit the threading of the thread through the eye at the free end of the lever. This outwardly projecting free end of the thread take-up lever not only spoils the appearance of the sewing machine, but this fast reciprocating free end projecting outwardly of the machine frame constitutes also a certain hazard since it may engage any objects accidentally brought into the path of the fast reciprocating end of the lever. Furthermore, passing the thread through the small eye in the free end portion of the lever is also a troublesome operation.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above disadvantages of sewing machines known in the art.

7 More specifically, it is an object of the present invention to provide a sewing machine in which the thread take-up lever does not project with a free end portion thereof outwardly of the frame of the sewing machine, but in which the free end of the thread take-up lever, which engages the sewing thread for pulling the same from a thread source, is protected by a cover mounted in fixed position in an appropriate opening formed in the machine frame.

It is a further object of the present invention to construct the free end of the thread take-up lever and the cover in such a manner that engagement of a thread portion with the free end of the take-up lever can be carried out in an extremely simple and efficient manner, regardless of the position of the free end portion of the thread take-up lever.

With these and other objects in view, which will become apparent as the description proceeds, the invention mainly comprises a hollow machine frame having an opening, a thread take-up lever having a free hookshaped end for guiding a sewing thread, in which the lever is mounted in the interior of the machine frame so that its hook-shaped end may move in the region of the aforementioned opening between an upper and a lower dead center position, and a cover fixed to the machine frame which substantially closes the opening in the frame. The cover is formed with slots therethrough permitting insertion of a thread into the hook-shaped end of the lever regardless of the position of the latter.

The cover is preferably substantially U-shaped in cross-section and has a pair of sidewalls and a front wall connecting the sidewalls and the slots are formed in the sidewalls of the cover and are open at the upper ends thereof and each has a lower end positioned to be substantially aligned with the hook-shaped end of the thread takeup lever in the lower dead center position of the latter.

The opening in the machine frame is formed in the front wall of the latter and extends through the portion thereof aligned with the upper open ends of the slots into the top wall of the machine frame and the cover is fastened to the machine frame so that the front wall of the cover is flush with the front wall of the machine frame so as to provide a very neat appearance.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a sewing machine provided with a cover for protecting the free end of a thread take-up lever, not visible in FIG. ll;

FIG. 2 is a partial front view of the sewing machine shown in FIG. 1, partial in section and drawn to an enlarged scale;

FIG. 3 is a partial top view of the sewing machine;

FIG. 4 is a cross-section taken along the line A-A of FIG. 2;

FIG. 5 is a cross-section taken along the line B-B of FIG. 2;

FIG. 6 is a front view of the thread take-up lever and elements associated therewith; and

FIG. 7 is a perspective view of the cover for the thread take-up lever.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing, and more specifically to FIGS. 1 and 2 of the same, it will be seen that the hollow machine frame 2 of the sewing machine is formed in the front wall 32 thereof with an elongated opening 31 which is extended with a portion thereof into the top wall 30 of the frame, in which a cover 12 of a specific construction as will be described later on in detail is located to substantially close the opening formed in the machine frame. The main shaft 3 of the sewing machine is mounted in the interior of the machine frame 2 for turning movement about a horizontal axis in bearings 3 fastened to the machine frame, only one of which is shown in FIG. 2. During operation of the machine the main shaft l is rotated about its axis by drive means not shown in the drawing, since such drive means are of standard construction well known in the art and not forming part of the present invention. A crank 4, best shown in FIG. 4, is fixedly attached to the free, left end, as viewed in FIG. 2, of the main shaft 1 for rotation therewith. A crank pin 5 fixed to the crank 4 radially displaced from the axis of the main shaft 11 projects laterally from the crank 41.

The thread take-up lever, best shown in FIG. 6, has a substantially L-shaped configuration and one arm '7 of the lever is pivotally connected to the crank pin 5, whereas the lever portion 6 has an upper convexly curved face 6', and the lever portion 6 is provided at its free right end, as viewed in FIG. 6, with an upwardly extending hook-shaped thread guide portion 11, the inner surface 11 thereof has a small radius of curvature r in the order of l to 2 millimeters having its center at O and this inner surface of the hook-shaped end por' tion llll blends with the convexly curved surface 6'. A link '9 is pivotally connected at to the thread take-up lever, whereas the other end of the link 9 is pivotally connected, as shown in FIG. 4, to a pin 8 mounted in stationary position on the machine frame 2.

As evident from this construction, the hook-shaped end 11 of the thread take-up lever will move, during rotation of the main shaft 1 about its axis, from an upper dead center position P shown in full lines in FIG. 4 to an intermediate position M and from there to a lower dead center position Q shown in dash-dotted lines in FIG. 4.

The hook-shaped end portion 11 of the thread takeup lever reciprocates in vertical direction in the region of the opening 31 formed in the front wall of the machine frame 2 and to protect this end portion of the lever a cover 12 is provided in the aforementioned opening, which cover has a configuration as best shown in FIG. 7. As shown in this Figure, the cover 12 has a pair of substantially parallel sidewalls 12, 12 which are connected along the longitudinal front edges thereof by a front wall 12 so that the cover 12 has a substantially U-shaped cross-section. One of the sidewalls 12 is provided with a pair of fastening portions 13, 13 each formed with a bore therethrough through which fastening screws 14, best shown in FIG. 4, respectively extend for fastening the cover to the machine frame. Each of the sidewalls 12 is formed with an elongated slot 15 therethrough which is open at its upper end and which is defined by a pair of edge portions 15 and 15 The edge portion 15 of each slot is curved as clearly shown in FIGS. 4 and 7 to extend nearly parallel to the line 16' along which the center of curvature O of the hook-shaped end portion 11 of the thread take-up lever moves during movement of the latter from the lower dead center position Q to the upper dead center position P. The lower closed end of each slot 15 is located substantially aligned with the location of the center of the hook-shaped end portion 1 l in the lower dead center position Q of the latter. The cover 12 is fastened to the machine frame 2 in such a manner that the upper open ends of the slot are aligned with the part of the opening which extends into the top wall of the machine frame.

The sewing machine 100 is further provided with a thread tension device or threaded tension means for maintaining the thread upstream of the hook-shaped end portion 11 in tensioned condition, and comprising a pair of adjacent brake disks 21 turnably mounted adjacent to each other in the machine frame and pressed against each other by a spring not shown in the drawing, the tension of which may be adjusted in a known manner not forming part of the present invention by a tension adjusting member so that a thread 23 passed between the disks may be braked, and a thread take-up spring 22 wound about a pin, as shown in FIG. 2, and having a projecting curved end portion, as shown in FIG. 5, over which a thread 23 is guided. The machine includes further thread guide pins l7, l8 and 19, positioned and arranged on the various elements of the machine as clearly illustrated in FIGS. 2 and 4. As shown in FIG. 7, the guide pins 17 and 18 project from opposite sidewalls of the cover 12.

The above-described elements of the machine will cooperate with each other in the following manner:

A thread 23 taken from a thread source, not shown in the drawing, is passed between the two disks 21 as shown in FIGS. 2 and 5 and guided in downward direction over the guide pin 17, beneath the hook-shaped end portion of the thread take-up spring 22, then in upward direction and is inserted into the slots 15 formed in the sidewalls 12' of the cover 12 to engage directly in the hook-shaped end portion 11 of the thread takeup lever or on the upper convexly curved guide face 6' of the lever portion 6, depending in which position the thread take-up lever is during the threading of the thread 23. Subsequently thereto, the thread 23 is guided over the pins 18 and 19, through the thread guard 24 and the eye formed in the sewing needle 25.

The thread 23 may be brought in a very convenient manner into proper engagement with the hook-shaped end portion 1 l of the thread take-up lever regardless of the position of the latter during threading of the thread. If the hook-shaped end portion 11 of the lever should be located at M, indicated in dash-dotted lines in FIG. 4, the thread 23 passed into the slots 15 will first engage the convexly curved upper guide portion 6 of the lever and during subsequent movement of the latter from the position M to its lower dead center position 0, the thread will be guided by the left edge portion 15" of the slots, as viewed in FIG. 4, automatically into the hook-shaped end portion 11 of the lever when the latter reaches its lower dead center position Q. The same evidently holds true with regard to any other position of the lever.

In the arrangement according to the present invention, the end portion of the lever does not project outwardly from the machine frame as in sewing machines known in the art, but this end portion is protected by the cover 12. Nevertheless, the sewing thread can be properly engaged with the hook-shaped end portion 11 of the lever by the specific construction of the slots 15 formed in the sidewalls of the cover 12. This greatly facilitates threading of the thread 23, especially since the free end of the thread take-up lever is not formed with an eye as common in sewing machines known in the art, but in which the free end portion of the thread take-up lever is in form of an upwardly extending hook. The cover 12 is fastened in the opening of the machine frame so that the front wall of the cover is flush with the front wall of the frame thereby providing a very neat appearance of the sewing machine.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of sewing machines each provided with a take-up lever having a free end portion which is protected by a cover differing from the types described above.

While the invention has been illustrated and described as embodied in a sewing machine in which the free end portion of the thread take-up lever is hookshaped and protected by a cover located in an opening of the machine frame and formed with slots facilitating threading of a sewing thread into the hook-shaped end portion of the lever, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic of specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

1. In a sewing machine, a combination comprising a hollow machine frame having a front wall and a top wall and being provided in said front wall with an opening which extends with a portion thereof into said top wall; a thread take-up lever having a free hook-shaped end for guiding sewing thread, said lever being mounted in said machine frame so that its hook-shaped end moves in the region of said opening between an upper and a lower dead center position; and a cover having a pair of side walls and a front wall connecting said side walls and being formed in said side walls with slots having upper open ends and lower closed ends, said cover being fixed to said machine frame so that the upper open ends of said slots are aligned with said portion of said opening in said top wall of said machine frame, so that the lower closed ends of said slots are substantially aligned with said hook-shaped end of said thread take-up lever in said lower dead center position, and so that the front wall of said cover is flush with said front wall of the machine frame.

2. In a sewing machine, a combination comprising a hollow machine frame having an opening; a thread take-up lever having a free hook-shaped end for guiding sewing thread, said lever being mounted in said ma chine frame so that its hook-shaped end moves in the region of said opening along a curved path between an upper and a lower dead center position; and a cover fixed to said machine frame and substantially closing said opening, said cover having a pair of side walls shaped formed with slots therethrough which extend substantially aligned with the curved path which said hookend describes during its movement from said lower to said upper dead center position so that rubbing of a thread portion passing through the slots on the edges defining the slots during upward movement of said hook-shaped end is avoided.

3. A combination as defined in claim 1, wherein said thread take-up lever has an upper convexly curved surface.

4. A combination as defined in claim 3, wherein said hook-shaped free end of said lever opens in upward direction and has an inner surface blending with said convexly curved upper surface of said lever.

5. A combination as defined in claim 1, and including means for moving said thread take-up lever between the positions thereof, said means comprising a substantially horizontal main shaft turnably mounted in said machine frame, a crank fixed to said main shaft for turning therewith and having a crank pin radially displaced from the axis of said main shaft, said thread take-up lever having an arm portion pivotally connected to said crank pin, and a link pivotally connected at an end to said frame and at the other end to said arm portion at a point thereof spaced from said crank pin.

6. A combination as defined in claim 1 and including means for maintaining a thread upstream of said hookshaped end portion of said lever in tensioned condition.

7. A combination as defined in claim 6, wherein said means comprise a pair of brake disks between which the thread is guided and a take-up spring located downwardly of said brake disks and having a curved free end portion under which the thread is passed.

=l =l =l= 

1. In a sewing machine, a combination comprising a hollow machine frame having a front wall and a top wall and being provided in said front wall with an opening which extends with a portion thereof into said top wall; a thread take-up lever having a free hook-shaped end for guiding sewing thread, said lever being mounted in said machine frame so that its hook-shaped end moves in the region of said opening between an upper and a lower dead center position; and a cover having a pair of side walls and a front wall connecting said side walls and being formed in said side walls with slots having upper open ends and lower closed ends, said cover being fixed to said machine frame so that the upper open ends of said slots are aligned with said portion of said opening in said top wall of said machine frame, so that the lower closed ends of said slots are substantially aligned with said hook-shaped end of said thread take-up lever in said lower dead center position, and so that the front wall of said cover is flush with said front wall of the machine frame.
 2. In a sewing machine, a combination comprising a hollow machine frame having an opening; a thread take-up lever having a free hook-shaped end for guiding sewing threAd, said lever being mounted in said machine frame so that its hook-shaped end moves in the region of said opening along a curved path between an upper and a lower dead center position; and a cover fixed to said machine frame and substantially closing said opening, said cover having a pair of side walls formed with slots therethrough which extend substantially aligned with the curved path which said hook-shaped end describes during its movement from said lower to said upper dead center position so that rubbing of a thread portion passing through the slots on the edges defining the slots during upward movement of said hook-shaped end is avoided.
 3. A combination as defined in claim 1, wherein said thread take-up lever has an upper convexly curved surface.
 4. A combination as defined in claim 3, wherein said hook-shaped free end of said lever opens in upward direction and has an inner surface blending with said convexly curved upper surface of said lever.
 5. A combination as defined in claim 1, and including means for moving said thread take-up lever between the positions thereof, said means comprising a substantially horizontal main shaft turnably mounted in said machine frame, a crank fixed to said main shaft for turning therewith and having a crank pin radially displaced from the axis of said main shaft, said thread take-up lever having an arm portion pivotally connected to said crank pin, and a link pivotally connected at an end to said frame and at the other end to said arm portion at a point thereof spaced from said crank pin.
 6. A combination as defined in claim 1 and including means for maintaining a thread upstream of said hook-shaped end portion of said lever in tensioned condition.
 7. A combination as defined in claim 6, wherein said means comprise a pair of brake disks between which the thread is guided and a take-up spring located downwardly of said brake disks and having a curved free end portion under which the thread is passed. 